Fabrication and Adsorption Behavior for Congo Red of Chitosan and Alginate Sponge

Abstract

With chitosan and sodium alginate as the main raw material, the sponge adsorbents were satisfactorily prepared by freeze-drying and curing molding by CaCl₂. The structure of sponge was characterized by FTIR and SEM and its physical property was measured.

In addition, the different influences on absorbability of CR and analyzing the dynamics and thermodynamics of the adsorption process have been studied, thus it can provide theoretical foundation for the practical application of azo-dye wastewater treatment. The results are as follows: 0.10 g CTS/SA sponge adsorbent has the best absorbability on CR in the condition of 30°C, pH value is range from 6.00 to 7.00, and adsorption time is 45 min and stirring speed of 200 rpm. The adsorption kinetic followed the pseudo-second-order dynamics and it shows good relevance. The CR adsorption of CTS/SA sponge adsorbent can be described as Freundlich isotherm model (R2 > 0.94) and Langmuir isothermmodel (R2 > 0.99). The maximum adsorption capacity of CTS/SA sponges at 30°C can be obtained from the Langmuir model was 121.95 mg/g.

Keywords:

• Chitosan
• sodium alginate
• sponge
• congo red
• absorption